1. Field of the Invention
The present invention relates to an optical waveguide structure utilizing a slab-type and two-dimensional photonic crystal.
2. Related Art Statement
An optical device utilizing a photonic crystal has a structure of repeating different kinds of dielectric materials having different dielectric constants. According to such devices, the internal multiple reflection phenomenon is utilized to provide various kinds of devices having superior functions and of very small sizes. Since the principle of function of the device is based on multiple reflection phenomenon, the device properties have a strong dependency on frequency (wavelength) in the vicinity of a specific frequency. The frequency is decided upon the material (refractive index N) of a substrate for a photonic crystal and a length d of period of repetition of the photonic crystal structure. The dependency of the device on frequency is characteristic to the device. However, in the case that the device is used in a wide range of wavelength, the characteristics would turn to be a defect.
An optical waveguide utilizing a slab-type and two-dimensional photonic crystal is described, for example, in the following documents.
Japanese patent publication No. 2005-172932A
Japanese patent publication No. 2003-156642A
Japanese patent publication No. 2005-70163A
Japanese patent publication No. 2002-350657A
The 53'th Applied Physics Related Associated Lectures; Proceedings; (2006, Spring, at Musashi Kogyo University) page 1121, 23a-L-4
“2D PC Slab add/Drop Filter Integrated with Polarization Mode Converter” authored by Yoshinori TANAKA et. al.
Journal of IEICE, C, Vol. J87-C No. 1 pages 12 3˜131, January, 2004, “Finite element Method for Nonreciprocal Optical Waveguide_Discontinuity Problems and Analysis of Optical Isolators Using Magneto-Photonic Crystal Waveguide” authored by Kono et. al.
2001 The American Physical Society ┌PHYSICAL REVIEW LETTERS┘ Vol. 87, No. 25 ┌Extremely Large Group-Velocity dispersion of Line-Defect Waveguides in Photonic Crystal Stabs┘